The present invention relates to an inflatable air bag cushion for use in covering a side portion of a vehicle interior adjacent to an occupant to be protected during a collision event, and more particularly to an inflatable air bag cushion of substantially curtain-like structure for covering the side portion of the vehicle interior which air bag cushion is deployable from the region of the roof rail of the vehicle and which includes inflatable stiffening elements disposed in an arrangement along the lower edge of the cushion.
It is well known in motor vehicles to provide an air bag cushion for protecting a vehicle occupant wherein the air bag cushion is in fluid communication with an inflator for generating gas to inflate the cushion upon sensing predetermined vehicle conditions such as deceleration exceeding a certain level. It is further known to provide air bag systems including inflatable restraint cushions which are deployed in substantially curtain-like fashion between an occupant to be protected and the side portions of the vehicle adjacent to such occupant so as to provide the occupant with cushioning restraint during a side impact or extended roll-over collision event.
It has recently been proposed to provide inflatable air bag cushions which are deployable from stored positions along the roof rail of the vehicle so as to extend downwardly away from the roof line of the vehicle in substantially covering relation to the side portions of the vehicle against which the occupant may otherwise be thrown during a side collision or extended roll-over event. Such deployment is effected by the introduction of an inflating gas into the air bag cushion which thereby expands the cushion and forces it to move downwardly over the portions of the vehicle to be covered.
In some instances it is believed to be desirable for the deployed air bag cushion to extend across the window openings of the vehicle so as to block the occupant of the vehicle from being ejected from the vehicle interior during a side collision or roll-over event. In such a configuration, it is desirable that the cushion assumes a substantially taut configuration across the expanse of the vehicle to be covered so as to form a substantially stable barrier between the occupant and the covered expanse.
It is believed that in those environments where a curtain-like cushion is deployed downwardly over some portion of the window openings in a vehicle, the desired taut orientation over the covered expanse may be achieved to some degree by filling the air bag cushion with inflation gas which thereby tends to shorten the overall length of the cushion as available material expands outwardly. However, it has been found that as the area of coverage is increased, the volume of gas which is required to inflate and thereby stiffen the entire cushion structure may dictate the use of a prohibitively large volume of inflation gas. Moreover, the inflation gas which fills the lowermost portions of the air bag may provide little benefit to the occupant to be protected since in such regions the air bag cushion is intended to provide a primarily restraining rather than a cushioning function. Thus, if the curtain is to cover a significant expanse, prior configurations may require the use of significant volumes of inflation gas which may exceed the capacity of some inflators.
This invention provides advantages and alternatives over the prior art by providing an air bag cushion which is deployable in curtain-like fashion across the sides of a vehicle interior over an expansive area adjacent to the occupant to be protected. The air bag cushion may be expanded to a taut orientation without utilizing extensive quantities of inflation gas. In particular, the air bag cushion of the present invention may be deployed from a storage position along the roof rail of the vehicle downwardly over the window openings of the vehicle to assume an orientation which assists in holding an occupant within the vehicle during an extended roll-over event while at the same time reducing the volume of inflation gas utilized in the lower regions of the curtain structure.
Upon deployment of the cushion it is stiffened across its body by the inflated outward expansion thereof. However, in order to avoid the use of an extensive quantity of inflation gas, the cushion of the present invention includes segments of substantially noninflatable character which extend along the lower edge of the cushion. Inflatable elongate finger-like spacing elements extend towards the lower edge between the segments of substantially noninflatable character such that the finger-like elements are in fluid communication with the inflated interior of the curtain structure. The inflation of the cushion thereby causes the inflatable finger-like elements to inflate and thereby expand outwardly. This outward inflation of the finger-like elements provides the cushion with a requisite degree of dimensional stability adjacent the lower edge both in terms of tension and elongate stiffness such that the cushion provides a stable restraining surface across the window opening without requiring inflation of the entire structure.
Preferably, the segments of the substantially noninflatable character which extend along the lower edge of the air bag cushion are arranged in a predefined pattern below impact regions across the air bag cushion for cushioning impact of the occupant during the collision event.
In accordance with a potentially preferred aspect of the invention, the inflatable elongate finger-like elements are characterized by a low volumetric capacity relative to the volume of the impact regions across the air bag cushion such that available inflation gas is directed primarily into such impact regions.
In accordance with a potentially preferred aspect of the invention, the segments of substantially non-inflatable character which extend along the lower edge of the air bag cushion may be formed by joining together opposing panels of material forming the air bag cushion in defined patterns by seaming or other appropriate means.
Advantageously, the utilization of the low volume inflatable finger-like elements to stabilize the lower portion of the air bag cushion permits the air bag cushion to assume the desired orientation over the side portions of the vehicle while nonetheless reducing the volume of inflation gas required to assume this orientation.